Electrical adapter



March 22, 1966 1. c. HoRvATH ETAL 3,242,455 v ELECTRICAL ADAPTER Filed April 9, 1964 INV T0125 l, f W

United States Patent Odice 3,242,455 Patented Mar. 22, 1966 3,242,455 ELECTRICAL ADAPTER .lohn C. Horvath, Monroe, and Charles Theodore Von Holtz, Bridgeport, Conn., assignors to Harvey Hubbell,

Incorporated, Bridgeport, Conn., a corporation of Connecticut Filed Apr. 9, 1964, Ser. No. 358,522 3 Claims. (Cl. 339-14) This invention relates to an electrical adapter and, more particularly, to a three wire grounding adapter for adapting an electrical plug connector having parallel line blades and a grounding pin to engage a grounded outlet of the crowfoot type.

Two types of grounding connectors are in wide-spread use for single phase applications. In one such connector, the plug employs a pair of spaced parallel blades for carrying the line currents. In addition to the two blades, the plug also carries a ground-ing pin which is customarily semi-cylindrical in shape. The blades and pin of the plug mate with matching openings in an outlet or a female connector body. Another type of connector which is widely employed is known as the crowfoot connector. In a connector of this type, the plug portion comprises three blades. No one of the blades is parallel to any other blade. The two line blades extend outwardly from one side of the center line of the plug and are angled toward each other. The grounding blade is somewhat longer, is positioned on the other side of the center line, and its major surfaces extend radially relative to the circular face of the plug.

It is often desired to form interconnections between the two types of connectors referred to above. For example, Ait is often desired to connect a grounding pin type of plug to a crowfoot outlet. For this purpose, a grounding adapter is employed. Grounding adapters, which are known to the prior art are relatively large and cumbersome. An exemplary type of such an adapter comprises a cylindrical body constructed of a nonconductive material, such as rubber or plastic. Blades arranged in the crowfoot configuration extend from one of the plane -faces of the adapter and are secured to the adapter body by suitable means such as riveting. The conductive material which forms each blade also forms an electrical terminal including a binding screw. The opposite end of the adapter is provided with openings which are arranged to receive the spaced parallel blades and grounding pin of an electrical plug. This portion of the adapter is formed with chambers therein which contain the female contacts for making electrical connections to the plug. When the adapter is assembled, each female contact at one end is connected to a blade at the other, the connections being made by means of wires which are secured to the binding screws. It will be obvious that such prior art adapters are bulky, that they employ a relatively large number of parts, and that several operations, including wiring, are necessary during their manufacture.

Accordingly, it is the primary object of this invention to provide an improved electrical adapter. Other objects are to provide such an adapter which requires a minimum number of parts, which is inexpensive to manufacture, which is smaller andl more compact than prior art adapters, and which is arranged to provide an interconnection betwecn a grounded pin connector and a crowfoot connector. The manner in which the foregoing objects are achieved will be more apparent from the following description, the appended claims, and the figures of the attached drawing, wherein:

FIG. 1 is a plan view of an adapter constructed in accordance with this invention;

FlG. 2 is an elevational View of the adapter of FIG. 1

showing the manner in which it may be connected with a plug P of the grounded-pin. type;

FIG. 3 is an enlarged cross section taken along the line 3 3 of FIG. 1;

FIG. 4 is an enlarged cross section taken along line 4 4 of FIG. 1;

FIG. 5 is a View of the grounding blade assembly used in this invention, .and

FIG. 6 is a view of a Contact blade assembly used in this invention.

ln the adapter of this invention, no separate connecting means are required between the male and female ends of the adapter.

The construct-ion of the adapter of the invention will -now be explained with particular reference to the drawing. The adapter of the invention is essentially cylindrical in shape and is formed from a base member 10 and a body member 12. The base and body members of the adapter are connected together by means of a bolt 14 and nut 16, the nut and head of the bolt being recessed into the adapter body in the manner customary for electrical connectors. Line blades 18-26 andl grounding blade 22 extend from the fiat end surface 24 of the base member 10. The end surface 26 of the body member 12 defines a pair of spaced parallel slots 28-30 and a grounding opening 32.

The base member 10 is provided with a liange 34 and the body member 12 is provided with a mating shoulder 36, as is most clearly shown in FIG. 4. Proper rotational alignment between the two members is provided by means of a semicircular locking tongue 3S (FIG. 3) on base 10 and a matching recess 40 on body 12. Further stability and alignment between the two members is provided by a semicircular shoulder 42 which extends downward from the base member 10 into a matching recess 44 provided in the body member 12.

Contained within the body member 12 and extending between its inner end surface and the open-ings 2S, 30, 32 are chambers 46, 48, 50. Chambers 52, 54, 56 in the base member 10 are aligned therewith and communicate with slotted openings in the end surface 24 which permit the line and grounding blades to project therefrom. The chambers 52, 54 are mirror images of one another and are each provided with an inner shoulder S8, 60 for use in positioning .the inner assemblies in a manner to be described.

In the adapter of this invention, t-he electrical connections between the male and female ends of the adapter are made by means of single conductive elements rather than by wiring. These conductive elements lmay be referred to as blade assemblies and are illustrated in FIGS. 5 and 6. Referring rst to PIG. 5, there is illustrated a grounding `blade assembly. This assembly consists 4of three elements which are lixedly secured to one another. These are the grounding blade 22, a centr-al binding plate 62, and a spring clip 64. The binding plate 62 is formed from an electrically -conductive sheet metal plate, such as copper, with three projecting extensions 6251, 62b, 62C, extending from the main body of the binding plate. The spring clip 64 is substantially U- shaped, and its legs 64a, 64b are flared at their ends and so spaced as to grip a grounding pin which is inserted therebetween. The grounding 'blade 22, binding plate 62 and spring yclip 64 are formed into a unitary assembly by means yof an extending stud 66 on the end of blade 22 which extends through matching holes in binding plate 62 and spring clip 64 and is riveted over as shown in FIG. 3. In assembling the adapter, the blade 22 is inserted through the radially aligned opening in the end surface 24 of base member 10 and the binding plate 62 is seated into chamber 56. When the 'base member 10 and body member 12 are assembled, the inner end surface of the Ibody member 12 bears against the ends of the binding plate legs 62a, 62h, 62C so as to retain the grounding blade assembly in position.

The construction of contact blade assembly 18 is shown in FIG. 6. The blade 18 is formed from 'a single elongated piece of copper formed from a sidewardly projecting extension 68 forming shoulders 68a, 68h. The left end of the line blade 18, as illustrated in FIG. 6, is bent from the main portion of the blade so as to be offset downwardly as illustrated at 70. The left end of the blade 'also deiines a laterally projecting tab 71. A contact spring 72 has one end riveted to the central portion of the blade 18 by means of rivet 74. The other end of spring 72 forms a spring elip with the left end of blade 18, the ends being suitably ared to receive the blade of a plug therebetween. It will be remembered that the adapter of this invention is designed to provide 'a connection between parallel line blades and la crowfoot connection. For this reason, the blade 18 is twisted, as at 76, so that both the spring clip end and the blade end will be properly aligned. In the illustration of FIG. 6, line blade 18 is twisted clockwise as viewed from the left end of the assembly along the longitudinal axis. The other contact blade assembly which includes line blade 20 is similarly formed but is a mirror image of the described contact blade assembly.

When assembling the adapter, the line blades 18, 20 are inserted in the correct slots in the surface 24 of base 10. The shoulder 68h of each Contact blade assembly abuts against either shoulder 58 or 60 `of base member so as to retain the blades in the correct longitudinal relationship. The tab 71 slides into a matching slot in body 12 4when the two members `are joined. After insertion of the grounding blade and the two contact blades, base member 10 and body member 12 are joined with one another and the bolt 14 tightened into nut 16.

It will be obvious that, by means of this invention, there is provided an inexpensive compact adapter for interconnecting a plug of the parallel blade, grounded pin type with an outlet of the crowfoot type. It will be noted that no Wiring is required between the two ends of the adapter but that unitary assemblies `are provided which extend completely through the adapter and perform the dual functions of male and female contacts. It will also be obvious to those skilled in the 'art t-hat a number of variations and modifications may |be made in this invention -without departing from its spirit and sc-ope. F or example, a similar technique could -be employed for constructing an adapter for use between `a plug of the crowfoot type and a grounded pin outlet. Accordingly, the foregoing description is to be construed as illustrative only, rather than limiting. This invention is limited only by the scope of the following claims.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. A three-wire grounding adapter for use between fa crowfoot connector and a grounding =pin connector which comprises: a body lformed of electrically insulating material and including iirst and second end faces; and three =blade :assemblies positioned within said body, two of said blade assemblies each comprising a blade of a single material twisted intermediate its ends, for connection to said crowfoot connector `at said first end face and to said grounding pin `connector at said second end face.

2. A three-wire grounding adapter for adapting an electrical plug connector having parallel line blades and a grounding pin to engage a grounded outlet of the crowfoot type, said adapter comprising: a body formed of electrically insulating material and including rst and second external faces, said body dening at least rst, second, and third chambers therein and further vdefining first and second spaced, parallel slots in said first face communicating, respectively, with said rst and second chambers and a grounding opening communicating with said third chamber; a first contact -blade member having one end positioned `within said rst chamber and the other end forming a contact blade extending through said second face to engage one line contact of said grounded outlet, said member being twisted about its longitudinal axis whereby said one end is substantially parallel to the slot communicating with said rst chamber; rst spring clip means secured to said one end of said rst contact blade member and including a first end resiliently bearing against said one end to receive one of said parallel line blades therebetween; a second contact blade member having one end positioned within said second chamber and the other end forming a contact blade extending through said second face to engage the `other line contact of said grounded outlet, said member lbeing twisted about its longitudinal axis whereby said one end is substantially parallel to the slot communicating with said second chamber; second spring `clip means secured to said one end of said second Contact blade member and including a first end resiliently bearing against said one end to receive the other of :said parallel line blades therebetween; and a grounding contact blade assembly having one end forming a female electrical connector positioned within said third chamber to receive the grounding pin of said plug connector inserted through said grounding opening, and the other end forming a contact blade extending through said second face to engage the grounding contact of said grounded outlet.

3. The adapter of claim 2 wherein said grounding Contact blade assembly comprises: electrically lconductive spring clip means including rst and second spaced parallel legs resiliently biased toward each other to receive said grounding pin therebetween; and an electrically conductive elongated blade member having a iirst end xedly secured to said spring clip means and the other end forming said contact blade.

References Cited by the Examiner UNITED STATES PATENTS 1,179,728 4/1916 Knapp 339-155 2,399,408 4/1946 Walk 339-154 X 2,966,651 12/1960 Von Holtz 339-14 FOREIGN PATENTS 218,906 3/ 1957 Australia. 1,082,645 6/ 1960 Germany.

JOSE-PH D. SEERS, Primary Examiner. PATRICK A. CLIFFORD, Examiner, 

1. A THREE-WIRE GROUNDING ADAPTER FOR USE BETWEEN A CROWFOOT CONNECTOR AND A GROUNDING PIN CONNECTOR WHICH COMPRISES: A BODY FORMED OF ELECTRICALLY INSULATING MATERIAL AND INCLUDING FIRST AND SECOND END FACES; AND THREE BLADE ASSEMBLIES POSITIONED WITHIN SAID BODY, TWO OF SAID BLADE ASSEMBLIES EACH COMPRISING A BLADE OF A SINGLE MATERIAL TWISTED INTERMEDIATE ITS ENDS, FOR CONNECTION TO SAID CROWFOOT CONNECTOR AT SAID FIRST END FACE AND TO SAID GROUNDING PIN CONNECTOR AT SAID SECOND END FACE. 